The present invention relates to a gangway bellows cover-style connecting device for articulated vehicles.
In articulated or jointed vehicles, such as city buses, the connection between the two coaches of which the vehicle consists is made by means of rotary platforms able to allow both passenger transit and standing in the connecting zone.
The connection must, necessarily guarantee safety conditions even when the vehicle takes a bend, that is to say, even when the two coaches are not aligned with each other.
There are prior art connecting devices consisting of a substantially U-shaped gangway bellows cover connected to the rotary platform which forms a tunnel for transit between the two coaches.
The ends of the gangway bellows cover are connected to the free ends of the two coaches, in such a way that the gangway bellows cover deforms when the vehicle adopts configurations in which the two coaches are not aligned.
In particular, the gangway bellows cover-style connecting device has an accordion shape, that is to say, it has a plurality of U-shaped bands made of flexible material, usually plasticized fabric, which are joined together longitudinally.
Usually, passing below the rotary platform there are cables and pipes needed for correct operation of the rear/front coach.
The above-mentioned connecting devices therefore also extend below the rotary platform, to offer shelter for and allow correct passage of the above-mentioned cables and pipes.
The prior art also includes closing the U-shaped gangway bellows cover by providing a closing panel connected to the gangway bellows cover and positioned below the rotary platform.
The closing panel is designed to protect the cables and pipes from the outside environment, preventing them from getting damaged.
The closing panel is also designed to act as a shield for the rotary platform, protecting it from the outside environment both to avoid possible damage to it and to lessen the noise from the road surface striking the rotary platform (therefore increasing acoustic comfort for passengers).
In particular, the portion of gangway bellows cover extending below the rotary platform has its free ends folded towards the centre of the vehicle, in such a way as to create two substantially horizontal portions which are opposite each other.
The closing panel is rested on top of the above-mentioned two horizontal portions of the gangway bellows cover and is connected to them by Velcro strips.
The Velcro strips are applied along two opposite outer edges of the panel and on the above-mentioned horizontal portions of the gangway bellows cover.
This type of gangway bellows cover allows the removal of the closing panel for maintenance work on the rotary platform or cables and pipes extending below it, or to allow the latest generation low platform articulated vehicles to avoid positioning the closing panel in contact with the road surface, preventing it from deteriorating.
However, the connecting devices for articulated vehicles briefly described above have several disadvantages.
When the vehicle is taking a bend and the two coaches rotate relative to each other, the portion of gangway bellows cover on the inside of the bend tends to become compacted whilst the portion on the outside of the bend extends.
In this configuration the closing panel also tends to narrow at the portion facing the inside of the bend.
The Velcro strips positioned on the panel in the portion facing the inside of the bend deform, creating undulations to follow the deformation of the panel and the gangway bellows cover.
Those undulations in the Velcro tend to detach the closing panel from the gangway bellows cover, especially if while taking the bend the vehicle encounters irregularities in the road surface which cause stresses in various directions on the gangway bellows cover and on the closing panel.
It should be noticed that, since the closing panel is resting on top of the above-mentioned two horizontal portions of the gangway bellows cover, any mechanical stress to which the gangway bellows cover is subjected is transmitted to the closing panel, contributing to an increase in the tendency of the closing panel to detach when the vehicle takes a bend.